Multicasting in an online gaming system

ABSTRACT

An online gaming multicast service system includes a set of interconnected multicast managers (MM 1,  MM 2,  MM 3 ) for receiving messages from game servers (GS 1,  GS 2 ) to end-users (A-H). Each message and an associated end-user recipient list ({B,E,F}, {A,G,H}) is received by one of the multicast managers. The multicast service system further includes a set of multicast servers (MS 1,  MS 2,  MS 3 ), one multicast server being connected to each multicast manager, for distributing each message to all end-users in the associated end-user recipient list. Each multicast manager includes means for determining which recipients in an end-user recipient list associated with a message are connected to which multicast server and for dividing the end-user recipient list into corresponding end-user recipient sub-lists. Each multicast manager also includes means for forwarding the message and non-empty end-user recipient sub-lists to the respective multicast servers for further distribution of the message to the end-users in each non-empty end-user recipient sub-list.

This application is the U.S. national phase of International ApplicationNo. PCT/SE2009/050688, filed 8 Jun. 2009, which designated the U.S., theentire contents of which is hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates generally to online gaming systems, andespecially to multicasting in such systems.

BACKGROUND

Some events taking place in an online gaming system should be multicastto a large group of end-users connected to the system. For example, anotification about the start of a tournament should be sent out to allthe end-users registered to participate. Traditionally, this type ofdistribution mechanism is implemented directly inside the game servers.This solution, however, limits the ability to scale efficiently as thenumber of end-users grows. The main reason for this is that allend-users that should receive the event notification must somehow beconnected to the single game server where the event was triggered. Sincethe capacity of a single game server is limited, there is an upper boundon the number of end-users that a game server can manage to multicastto.

The multicast problem is similar to the scalability problem that ariseswhen trying to broadcast large amounts of data to many end-users in realtime, e.g. live streaming on the internet. The main difference is thatmulticast, as opposed to broadcast, is directed to a specific set ofend-users. The game servers must distinguish between different end-usersand determine which ones that should receive a specific message. Simplybroadcasting everything to everybody is not an option here, since thiswould violate security principles of sensitive data. It would alsogenerate unnecessary data traffic which increases the operating costs.

Another drawback of the described traditional multicast mechanism isthat it is part of the gaming domain, i.e. the logical group ofapplications that manage game related logic. However, the gaming domainshould be kept as clean as possible and optimized for its purpose—tomanage game states and uphold the game rules. By connecting end-usersdirectly to the game server for multicast purposes, the game serverresponsibility is stretched outside the gaming domain. The game logicmust then also consider details about end-user connections that are ofno relevance to the game itself. The mix of multicast connection logicand game logic does not only increase the complexity of the gameservers, it also limits the performance of each game server. Anapplication can typically be optimized for efficient IO throughput orfor efficient rule processing—but not for both. The mix implies atrade-off where the game servers need to sacrifice game rule processingperformance to handle large numbers of end-user multicast connections.

SUMMARY

An object of the present invention is to provide more efficientmulticasting in an online gaming system.

This object is achieved in accordance with the attached claims.

Briefly, an online gaming multicast service system in accordance withthe present invention includes a set of interconnected multicastmanagers for receiving messages from game servers to end-users. Eachmessage and an associated end-user recipient list are received by one ofthe multicast managers. The multicast service system further includes aset of multicast servers, one multicast server being connected to eachmulticast manager, for distributing each message to all end-users in theassociated end-user recipient list. Each multicast manager includesmeans for determining which recipients in an end-user recipient listassociated with a message are connected to which multicast server andfor dividing the end-user recipient list into corresponding end-userrecipient sub-lists. Each multicast manager also includes means forforwarding the message and non-empty end-user recipient sub-lists to therespective multicast servers for further distribution of the message tothe end-users in each non-empty end-user recipient sub-list.

BRIEF DESCRIPTION OF THE DRAWING

The invention, together with further objects and advantages thereof, maybest be understood by making reference to the following descriptiontaken together with the accompanying drawings, in which:

FIG. 1 is a block diagram illustrating traditional multicasting in anonline gaming system;

FIG. 2 is a block diagram illustrating multicasting in an online gamingsystem in accordance with an embodiment of the present invention;

FIG. 3 is a block diagram illustrating multicasting of a specificmessage in the online gaming system of FIG. 2;

FIG. 4 is a block diagram illustrating multicasting of another specificmessage in the online gaming system of FIG. 2; and

FIG. 5 is a block diagram illustrating an embodiment of a multicastmanager.

DETAILED DESCRIPTION

In the following description the same reference designations willsometimes be used for elements having the same or similar functions.

Furthermore, in the figures of the following description connectionsbetween different entities are illustrated as separate logicalconnections. However, in reality the actual connections may bemultiplexed on fewer inputs and outputs.

FIG. 1 is a block diagram illustrating traditional multicasting in anonline gaming system. A gaming domain 10 includes a number of gameservers GS1, GS2, . . . , GSn. A typical gaming domain will include 3-7game servers. Each game server is connected to a corresponding end-userset 1, 2, . . . , n. A typical end-user set may include 5000-15000end-users. The union of all these sets form the gaming domain end-userset. During gaming sessions the game servers use these connections forindividual communication with the end-users. It is to be noted that aspecific game may involve end-users spread over several game servers(This is handled by interconnecting the game servers, as illustrated inFIG. 1.). However, the same connections are also used for multicastingmessages to subsets of the gaming domain end-user set. The multicastingis managed by the game servers themselves, and typically involvesseveral game servers, since an event triggering a message occurs on onegame server and the end-users intended to receive the message may bespread over several game servers.

FIG. 2 is a block diagram illustrating multicasting in an online gamingsystem in accordance with an embodiment of the present invention. Toavoid cluttering of the figure, only two game servers GS1, GS2 and a fewend-users A-H have been drawn. However, as indicated above, the actualnumbers (especially the number of end-users) are typically larger. Theend-users are connected to the game servers for individual communicationas in FIG. 1 for gaming, but message multicasting will be handled by aseparate system, as will be described below. In the example, game serverGS1 is assumed to manage the end-user set {A,D,E,F} and game server GS2is assumed to manage end-user set {B,C,G,H}. These “gaming connections”are not shown to avoid cluttering of the figure. The interconnectionbetween the game servers has been omitted for the same reason.

In the embodiment illustrated in FIG. 2, messages from game servers GS1,GS2 are not sent separately to each end-user recipient, as in FIG. 1.Instead they are sent only once to a multicast service system 12, whichdistributes them to each end-user recipient. This multicast servicesystem includes a number of interconnected multicast managers MM1, MM2,MM3 receiving multicast messages, which are forwarded to multicastservers MS1, MS2, MS3, one for each multicast manager, which distributethem to the end-user recipient. When a multicast message is sent fromone of the game servers GS1, GS2, it is received by one of the multicastmanagers MM1, MM2, MM3. This multicast manager will transfer the messageto its associated multicast server for distribution to the end-userrecipient connected to it. The end-user recipient that are not connectedto this multicast server will be reached by sending the message to othermulticast managers over the appropriate inter-connection lines L12, L13,L23 for further distribution on the other multicast servers to theremaining end-user recipient. This process will be illustrated withreference to FIGS. 3 and 4.

In a preferred embodiment a load balancer LB is provided between thegame servers and the multicast managers. The purpose of the loadbalancer is to avoid overloading of one of the multicast managers. Inthe example the load balancer may cycle through the multicast managersby sending a first message from one of the game servers to multicastmanager MM1, a second message from one of the game servers to multicastmanager MM2, a third message from one of the game servers to multicastmanager MM3, and repeat this pattern for subsequent messages. Anotherpossibility is to randomly send ⅓ (in average) of the received messagesto each multicast manager.

FIG. 3 is a block diagram illustrating multicasting of a specificmessage in the online gaming system of FIG. 2. In this example gameserver GS1 sends a message (represented by the envelope) to the end-userset {B,E,F}. This is accomplished by sending the actual message and anend-user recipient list {B,E,F} associated with this message to themulticast service system 12. It is noted that end-user B is included inthis list, although this end-user is actually managed by game serverGS2. Thus, in this case the game associated with this message is spreadover several servers, as described above. Although game server GS1 doesnot manage end-user B, it may still include it in the end-user recipientlist associated with the message.

The message with its end-user recipient list is received by one of themulticast managers, MM3 in the example, preferably after passing throughload balancer LB, which selects which multicast manager to use. Themulticast manager MM3 processes the end-user recipient list associatedwith the message to determine which end-user is associated with whichmulticast manager (or server, since they are paired together). In thiscase end-user F is associated with multicast manager MM3. Thus,multicast manager MM3 sends the message as well as an end-user recipientsub-list {F} to multicast server MS3, which sends the message toend-user F. The multicast manager MM3 also sends the message and anend-user recipient sub-list {B} to multicast manager MM1 oninterconnecting line L13, which forwards this information to multicastserver MS1, which in turn sends the message to end-user B. Similarly,multicast manager MM3 sends the message and an end-user recipientsub-list {E} to multicast manager MM2 on interconnecting line L23, whichforwards the information to multicast server MS2, which in turn sendsthe message to end-user E.

FIG. 4 is a block diagram illustrating multicasting of another specificmessage in the online gaming system of FIG. 2. In this case game serverGS2 sends a message to the end-user set {A,G,H} over multicast managerM1. Multicast manager MM1 processes the end-user recipient list of themessage to determine which end-user is associated with which multicastmanager. In this case end-user A is associated with multicast managerMM1. Thus, multicast manager MM1 sends the message as well as anend-user recipient sub-list {A} to multicast server MS1, which sends themessage to end-user A. The multicast manager MM1 also sends the messageand an end-user recipient sub-list {G,H} to multicast manager MM3 oninterconnecting line L13, which forwards this information to multicastserver MS3, which in turn distributes the message to end-users G and H.In this example multicast manager MM2 is not used, since end-users D,Eare not in the end-user recipient list.

It is also noted that end-users C and D did not receive any of theexample messages in FIGS. 3 and 4. This is a further illustration of themulticasting feature that typically only proper subsets of the gamingdomain end-user set will receive messages.

FIG. 5 is a block diagram illustrating an embodiment of a multicastmanager, for example multicast manager MM1 in FIG. 2-4. A message andits associated end-user recipient list received by the multicast managerare forwarded to a recipient list extractor 20, which extracts the listand forwards it to a recipient list processor 22. This processor isconnected to a memory 24 storing a table with the identities A-F ofconnected end-users and their associated multicast managers (orequivalently, their associated multicast servers). Recipient listprocessor 22 compares the recipients of the received end-user recipientlist to the stored table and forms 3 end-user recipient sub-lists, whichare forwarded (if not empty) to respective recipient list adders 26, 28,30, where they are added to the message and sent to multicast serverMS1, multicast manager MM2 and multicast manager MM3, respectively.

The functionality described with reference to FIG. 5 is implemented ineach multicast manager. In particular each multicast manager willinclude a copy of the table in memory 24. The content this of table isupdated as end-users are connected to and disconnected from themulticast servers.

Although the multicast managers and multicast servers have beenillustrated as separate elements, they may also be integrated as asingle unit.

In summary, the multicast service system described above will employ amulticast manager internally to keep track of which end-users that areconnected to which multicast server. Each multicast manager is coupledto a single multicast server that manages the actual end-usercommunication. As an event is sent to the multicast service, it will berouted to a single multicast manager, preferably through a loadbalancer, for processing. The subsequent process can be described by thefollowing steps:

-   -   1. Iterate through the end-users recipient list.    -   2. For each recipient, resolve which multicast server the        end-user is connected to.    -   3. Forward the messages to the associated multicast server        together with the relevant recipient sub-list of end-users that        are connected locally (unless the sub-list is empty).    -   4. If there are remaining recipients connected to other        multicast servers, build an end-user recipient sub-list for each        of these multicast servers.    -   5. Forward the message and each end-user recipient sub-list to        the peer multicast manager(s).

In effect, this process will divide the distribution work among theavailable multicast servers and make sure that all recipient end-usersare reached regardless of where they are connected.

The functionality of the multicast service system of the presentinvention is typically based on micro processor systems runningcorresponding software.

The scalability aspect of the present invention is similar to thesolution commonly applied to solve the broadcasting problem describedabove. Servers are arranged in a tree structure where messages aredistributed from the root (the source of messages) to the leaves (whereend-users connect). Each leaf can only accept a limited number ofend-user connections, but scalability can still be achieved by addingmore leaves (multicast manager/server pairs). The main differencecompared to the broadcast solution is that the multicast mechanism mustalso be able to send messages to a restricted set of end-users. Thisimplies that the game server that initiates distribution of a multicastmessage must also provide a recipient list of end-users.

As described above, the present invention decouples the multicastmechanism from the game servers and introduces a new multicast servicein a layer between the game servers and the end-users. This solutionwill keep the gaming logic clean from infrastructural concerns such asthe transport mechanism(s) used to communicate with end-users.Furthermore it allows the multicast mechanism to scale as the number ofreceivers grows by fanning out the communication over several multicastmanager/server pairs.

The multicast servers are responsible for managing the end-userconnections. Apart from the actual distribution of messages this alsomeans that the multicast servers abstract the transport mechanism usedto communicate with the end-users. This effectively relieves the gameservers from this responsibility and allows the game servers to manageall end-users in the same way regardless of whether the end-user isconnected through a mobile phone, desktop client or is playing from theweb.

Furthermore, the multicast servers can be designed and optimized forefficient IO performance without having to consider game logic as well.Consequently, the game servers can be optimized for rule processingcapability. It should also be noted that the two types of servers; gamesservers and multi-cast servers, may now also scale separately. Thenumber of game servers in use is relative to the amount of ruleprocessing performance required. The number of multicast manager/serverpairs in use is relative to the number of connected clients. The resultis a more cost effective solution that consumes less hardware resourcesper end-user when scaling to meet the demands of a growing customerbase.

It will be understood by those skilled in the art that variousmodifications and changes may be made to the present invention withoutdeparture from the scope thereof, which is defined by the appendedclaims.

The invention claimed is:
 1. An online gaming multicast service system,including: a set of interconnected multicast managers for receivingmessages from game servers to end-users, each message and an associatedend-user recipient list being received by one of the multicast managers;a set of multicast servers, one multicast server being connected to eachmulticast manager, for distributing each message to all end-users in theassociated end-user recipient list; each multicast manager including: arecipient list processor for determining which recipients in an end-userrecipient list associated with a message are connected to whichmulticast server and dividing the end-user recipient list intocorresponding end-user recipient sub-lists, and means for forwarding themessage and non-empty end-user recipient sub-lists to the respectivemulti-cast servers for further distribution of the message to theend-users in each non-empty end-user recipient sub-list, and a memoryfor storing a table associating each end-user with a multicastmanager/server pair to which it is connected; wherein the recipient listprocessor is configured to determine the end-user recipient sub-listsusing the received end-user recipient list and the table.
 2. The systemof claim 1, wherein the game servers are connected to the multicastmanagers through a load balancer.
 3. An online gaming multicast servicesystem, the system comprising: a set of interconnected multicastmanagers for receiving messages from game servers to end-users, eachmessage and an associated end-user recipient list being received by oneof the multicast managers; and a set of multicast servers, one multicastserver being connected to each multicast manager, for distributing eachmessage to all end-users in the associated end-user recipient list;wherein each multicast manager includes: a memory configured to store atable associating each end-user with a multicast manager/server pair towhich it is connected, and a recipient list processor configured todetermine which recipients in an end-user recipient list associated witha message are connected to which multicast server, and divide theend-user recipient list into corresponding end-user recipient sub-lists,wherein the recipient list processor is configured to determine theend-user recipient sub-lists using the received end-user recipient listand the table, and wherein the multicast manager is configured toforward the message and non-empty end-user recipient sub-lists to therespective multi-cast servers for further distribution of the message tothe end-users in each non-empty end-user recipient sub-list.
 4. Thesystem of claim 3, wherein the game servers are connected to themulticast managers through a load balancer.